By MARCIE GEFFNER, bankrate.com

Declining house values create great opportunities for homeowners to contest their property tax bills and potentially save big money.

Each jurisdiction has its own rules, procedures and deadlines to appeal property taxes. The bottom line is that a little research, communication and patience can pay off when you fight a property tax bill.

Paying off your mortgage might sound like an ambitious plan, especially if you have recently refinanced into a 30-year term. But it's still smart for homeowners to give some serious thought as to how they'll pay off their home loan; if not in 2012, then sometime.

An early mortgage payoff can net substantial interest savings compared to making scheduled payments for 15 or 30 years.

Mortgage interest rates, near all-time lows, are likely to remain attractive throughout 2012. That means opportunities for new homebuyers and for homeowners who want to refinance.

Here are five reasons why you might want to get a new mortgage, and what you should know.

One reason some home sales fall apart is the buyer can't qualify for a mortgage loan. And one challenge for buyers and homeowners who want to refinance is they must prove to the lender they have enough income to afford the payments.

Meeting that standard isn't easy, says Carolyn Hastings, a broker associate at J. Rockcliff Realtors in Blackhawk, Calif.

Selling a home as is can save repair dollars, but the sales tactic has risks and other considerations sellers should keep in mind.

The main danger of selling a home as is comes from the possibility it will fetch a rock-bottom price. Sometimes, but not all the time, it's more cost-effective to pay for repairs to merit a higher purchase price.

Buying a home is a challenging goal for most hopeful homeowners. But for those who have experienced a bankruptcy, foreclosure or short sale, the hurdles are even higher.

Fail. Fallout. Fall apart. Bomb. Those are among the colorful phrases real estate agents use to describe home sales that do not close.

For buyers, a failed transaction might be disappointing. For sellers, the implications can be more painful, especially if local home values are declining, says David Moody, a broker at ERA Sunrise Realty near Athens, Ga.

Homebuyers don't want houses that stink. Sellers must identify and remediate odors that make prospective purchasers hold their noses and run for the exits.

A buyer's market is a tough challenge for sellers, says Patti Ketcham, owner of Ketcham Realty Group in Tallahassee, Fla.

Ask mortgage banker Michael Becker the age of his oldest-ever mortgage client, and he'll tell you: 97.

"She was lucid, owned her house outright and had retirement income," Becker, of WCS Funding Group in Lutherville, Md., says of his client. "She was helping out her son."

Homebuyers who have a credit score of 580 or better and a down payment of at least 3.5 percent of the home's purchase price might seem like good candidates for an FHA loan, insured by the Federal Housing Administration. But whether these borrowers will qualify for such a loan isn't quite so simple.